JPH0393637A - Production of glass - Google Patents

Abstract

PURPOSE:To readily produce void-free glass having a high quality by sintering a wet gel under pressure into glass in the production of the glass by a sol-gel method. CONSTITUTION:The sol of a component composition used for the objective glass and comprising a metal alkoxide and the fine particles of a metal oxide as main components is prepared and allowed to gelate in a closed container having a desired shape to prepare a wet gel. When glass is produced by a sol-gel method wherein the wet gel is subjected to a drying treatment and a thermal treatment such as a sintering treatment to form the glass, the glass formation process is performed under pressure.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is a quartz film that can be applied to optical parts such as lenses of projection exposure devices for integrated circuits, TPT substrates for liquid crystal displays, prisms, beam splitters, and spectrometers. This invention relates to a method for producing glass and various glasses with excellent optical properties by a sol-gel method.

[Traditional technique? Ifl In the production of glass by the conventional sol-gel method using metal alkoxides and fine particles of metal oxides as main raw materials, a liquid sol with the desired glass component composition is gelled and dried, and the resulting gel body is sintered and vitrified. in the atmosphere at normal pressure or
The experiment was carried out under reduced pressure and an inert gas atmosphere.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the problem that air bubbles remain inside the manufactured glass. Although bubbles can be reduced if carried out under an inert gas atmosphere or under an inert gas atmosphere, the level is not necessarily satisfactory for use in optical applications.

Therefore, an object of the present invention is to provide a method for easily producing high-quality glass by removing air bubbles by sintering and vitrifying under pressure.

[Means for Solving the Problems] The method for producing glass by the sol-gel method of the present invention involves preparing a liquid sol having a desired glass component composition using metal alphoxide and metal oxide fine particles as main raw materials, and converting the liquid sol into a desired glass component. In the sol-gel method, in which a wet gel is produced by gelling in a shaped sealed container, the wet gel is vitrified by heat treatment such as drying and sintering, and the vitrification is performed under pressure. do.

[Function] By carrying out the sintering process under pressure, the present invention eliminates the pores that cause bubbles caused by decomposition of moisture, organic organic groups, etc., and therefore eliminates the presence of bubbles inside the glass. Extremely high quality glass can be produced.

[Example] Ethyl silicate, ethanol, water, aqueous ammonia (2
9%) were mixed in a molar ratio of 1:7.6:4:(LO8) and stirred for about 3 hours, then allowed to stand at room temperature to grow and ripen the particles.After this, By concentrating under reduced pressure, a silica fine particle dispersion liquid with good dispersibility was prepared.

Next, using 1/4 amount of ethyl silicate than the previous ethyl silicate, add 102 N hydrochloric acid so that the weight ratio is 1:1, and stir for about 2 hours while cooling with ice to prepare a hydrolyzed solution. was prepared.

Here, the pH value of the silica fine particle dispersion was adjusted to 4.5 by adding 2N hydrochloric acid, and then a hydrolyzed solution of ethyl silicate was mixed therein and sufficiently stirred until a homogeneous liquid sol was obtained. After that, 11L2 normal ammonia water was added to the liquid sol, the pH value was adjusted to 50, and the diameter was 50cI.
The liquid sol was poured into a cylindrical mold II to a height of 103 mm. Furthermore, the container was sealed tightly with a lid to allow gelation to occur, thereby producing a wet gel. The wet gel was aged at room temperature for several days, and when the shrinkage was almost completed, it was transferred to a dry airtight container and dried in a constant temperature dryer maintained at 70°C. 1 cm *height 75
A cylindrical white gel of No. 1 was obtained.

The gel body thus obtained was heated to 1000111 in an oxygen and nitrogen atmosphere, and after various treatments such as promotion of condensation/reaction, dehydration, and removal of organic residues, 5M
The temperature was raised to 1500° C. under pressure of 150° C. to vitrify it.

The glass body obtained as described above is a highly transparent colorless cylinder, with a diameter of 15 cm, a height of 5 cm, and a weight of 1 cm.
, 940 f. The physical properties of the obtained glass were consistent with those of silica glass, including Vickers hardness, specific gravity, coefficient of thermal expansion, infrared and near-infrared absorption spectra, and refractive index. After further polishing the edge of the glass,
When the inside of the glass was observed under irradiation with a condensing lamp of 00,000 lux, no bubbles or foreign matter were found.

[Effects of the Invention] As described above, according to the method of the present invention, high-quality bulk glass with excellent optical properties can be easily produced. Therefore, we believe that its application will expand not only to fields where quartz glass has been used up until now, but also to a variety of other fields that require particularly high quality, such as photomask substrates for industrial use, optical fiber base materials, and special optical applications.

In addition, in the sol preparation step, B, Ti, Ge, Ma,
Oa, Li, At, To, Zr, Oe, 11d, Or,
It is possible to add various elements such as Ir, and it is easy to manufacture various types of multi-component glasses and glasses that are not made of existing glass.

that's all

Claims (1)

[Claims] (1) Prepare a liquid sol with a target glass component using metal alkoxide and metal oxide fine particles as main raw materials, gel the liquid sol in a sealed container of a desired shape to produce a wet gel, and then 1. A method for producing glass by a sol-gel method in which wet gel is vitrified by heat treatment such as drying and sintering, characterized in that the vitrification is carried out under pressure.